The Internet-of-Things (IoT) is the interconnection of various embedded devices. Such devices (called “things”) may or may not have user-accessible input/output capability. For example, a thing may be an embedded sensor inside of a product such as a refrigerator or washing machine. Such a thing may not have a mouse, keyboard, display or any other type of user-accessible device by which a person can digitally interact with the thing.
A portable sensor connected in an IOT can be used for various applications taking advantage of its compactability. In the course of developing various types of the gas sensor, they have been modified to meet the purpose of use and detection of a certain desired gas: through improvements on employed materials and applicable sensing apparatuses. As a result of these efforts, various types of the gas sensor have been commercialized to be used in industries, medical fields and daily lives. Particularly, wide distribution of liquefied natural gas (LNG) and liquefied petroleum gas (LPG) and public attention to socially issued problems of drunk driving and personal hygiene has led the gas sensor to be further commercialized in different types such as a portable leaking gas sensor, a portable alcohol analyzer, or a portable breath analyzer.